It’s probably no surprise to you, dear reader, that magicians love correspondences.  You know, “X corresponds to Y”, or “this rules that over there”.  You see it all the time in any occult art or science.  Not everyone likes them, and depending on the source the correspondences can be complete trash; ideally, you should listen to the correspondent and correspondee, but more often than not the correspondences work.  The bigger or more famous the force, the more correspondences the force is likely to have.  In ceremonial or Western magic, the biggest forces one can work with are, after Divinity itself, the planets and the elements.  So, naturally, it would make sense that magicians, especially Agrippa, have figured out correspondences between the two sets of forces:

• Fire: Mars, Sun
• Air: Jupiter, Venus
• Water: Saturn, Mercury
• Earth: Moon

This set of correspondences is suggested by Agrippa in his Table of Four (book II, chapter 7) and explanation of the elements in the heavens (book I, chapter 8), and has worked well for me in my own practice.  However, with the exception of the common-sense attributions of the Sun and Mars to Fire, the correspondences seem rather out of place .  Namely, they seem to run contrary to astrological rulerships or a generally-perceived elemental correspondence, which might run more like:

• Fire: Sun, Mars
• Air: Mercury
• Water: Moon, Jupiter(?)
• Earth: Saturn, Venus(?)

It makes sense that the Moon, ruling over the tides and the Female, would be watery, and Agrippa agrees that this is a common position to take; that Saturn, being slow, restrictive, and heavy, would be earthy; that Mecury, being fast, intelligent, and communicative would be airy.  Indeed, these are shown by their primary astrological rulerships, with the Moon presiding over Cancer, Saturn over Capricorn, and Mercury over Gemini.  But don’t forget that Saturn also rules over Aquarius, an air sign, and Mercury over Virgo, an earth sign.  Venus and Jupiter, too, rule over two signs each (earthy Taurus and airy Libra, and fiery Sagittarius and watery Pisces, respectively).  Simple astrology doesn’t appear to be helpful, then, in showing how the planets relate to the elements.

To explain Agrippa’s correspondences between the planets and elements, let’s start with the Sun and Mars, which are straightforwardly associated with Fire.  The Sun is the source of light and heat in our solar system, without which nothing could act; Agrippa calls it the “lucid flame”, and associates it with Fire.  Mars, likewise, for his hot temperament and sharp nature, both of which are associated with Fire.  Mars is associated over any sharp or bladed weapon, just as the Platonic solid of Fire is the tetrahedron (a d4, in RPG dice terms), due to its sharp and stinging nature.

The Moon is associated with Earth in Agrippa’s system, which is less astrological and more celestial.  In the geocentric heaven-based model of the cosmos, the heaven of the Moon is the closest to Earth, making it the most dense of the seven planets.  As the most dense planet, it’s the last stop for an Idea coming from the sphere of the Prime Mover through the stars and the other planets to finally come into form; this is the sphere where something actually takes a materialized shape, even if it’s only illusory and ephemeral.  This is also shown since, as the fastest moving planet and the lowest rung on the ladder, it collects the rays and forces of all the other planets and influences above it, focusing them like a lens onto the Earth (this is why the Moon is always considered as a co-significator in horary astrology, and why silver, the metal of the Moon, suffices for any planetary metal).  Like the element of Earth, which takes form and receives the influences of the other elements, the Moon takes form and receives the influences of the other planets.

Mercury is associated with Water.  Mercury’s planetary metal, actual mercury, is the only metal which is liquid at room temparture and standard pressure; this alone might explain its association with Water, at least on an alchemical level, but the correspondence reaches deeper than that.  Mercury is associated with every element and planet, since it’s notable for changing depending on what it’s nearby or aspected with, but it’s because of this adaptable nature that Mercury is associated with Water, which can likewise take on the attributions of whatever it’s nearby or mixed with.  Even though communiation is an airy act, it’s the act of connecting on a level of ideas untainted by concrete form that Mercury signifies; he’s the Messenger, after all, not the message itself.  Between concrete Earth and communicative Air, the Messenger has to travel from place to place and connect entity to entity, and it’s that connective principle of Water that identifies Mercury.

Saturn is also associated with Water, though this correspondence is slightly difficult to explain.  Qabbalistically, Saturn is associated with Binah, the Great Mother, the recepticle of all things that births things from the highest Supernals into the manifesting world; as the third sephirah or heaven, we can associate it with a figure made from three points, a triangle, specifically the downwards-pointing triangle which is the symbol for Water.  Seen as a symbol of boundaries, being the outermost planet from the Earth, Saturn has a very natural affinity for Water, where rivers and seas often formed natural boundaries to lands or claims thereof.  In classical Ptolemaic and Pythagorian systems, Saturn’s primary quality is cold, which is the primary quality of the element of Water (where Fire is primarily hot, Air is primarily moist, and Earth is primarily dry).  Saturn, as the planet representing depression, connects with Water in that Water is always constantly moving downwards, leading to decreased spirits and vitality; Earth, being also cold and dark, at least has stability and rigidity to it, but Water is emotionally volatile and will always seek the lowest possible state unless held up or back by another force.

Jupiter corresponds with Air, and though potentially awkward, it makes sense.  As a gas giant and the largest planet in the solar system, Jupiter rules expansion.  Expansion is a quality of gas, the phase state associated with the element of Air, since a gas fills the container it’s in.  Jupiter, as king of the planets and the heavens (think Jove or Zeus) necessarily involves oversight, education, and management from various quarters of the skies; although these things sound more mercurial at first, the massive network that rulership implies must be founded on Air.  Plus, as the planet that rules the humour of blood and the sanguine temperament, which are associated with Air, Jupiter must also be associated likewise.

Venus is the second planet asociated with Air.  Venus is the planet of love, of conjunction and unity between the Male and the Female.  Although the sign of Air is an upwards-pointing triangle with a horizontal line through it, another classical symbol for it is an upwards-pointing triangle overlaid with a downwards-pointing triangle of the same size, also known as the Star of David or hexagram.  The upwards-pointing triangle represents Fire and the Male, with the downwards-pointing triangle represents Water and the Female; fire, when added to water, yields a gas of steam, like masculinity added to feminity produces conjunction and love.  Even though Venus is shown as being associated with water and the oceans (and, indeed, Agrippa also has Venus signify watery things), passion and love are not formed from pure emotion alone; emotion must be whipped up into passion, as waves are by water with wind.  While water may signify empathy, true human connection must be made with communication of that empathy, and communication is done primarily through Air.

Also, although not a planet, Agrippa mentions that the fixed stars are corresponded with the element of Earth as well.  Being fixed and immutable in the sphere of the fixed stars, between the heavens of Saturn and the Prime Mover, these celestial lights are found in the dark of the sky much as gems are in the dark of the earth.  Their influences don’t change, and their positions change only slightly with the precession of the equinoxes and relative to themselves.  Having such a rigid relationship to our sphere, the correspondence between the fixed stars and Earth makes sense.